<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .top {
            height: 20px;
            background-color: green;
        }

        .middle {
            height: 500px;
            background-color: darkorange;
        }

        .bottom {
            height: 20px;
            background-color: pink;
        }
    </style>
</head>
<body>
<div class="main">
    <div class="top"></div>
    <div class="middle"></div>
    <div class="bottom"></div>
</div>
</body>
</html>